My son, 8, loves to have me watch him play plants vs zombies. (I'm way better, btw. My technique, which seems like the only logical one, is to buy tons of sun producing items in the beginning and fend off the zombies with the free or cheap shooters. At the end of levels I have an excess of 1000 sun points)
2 Onions at the end of the outer (and middle lane). With spikes to the right of them if there are vehicles. Sunflowers behind those. Then you're down to 2 lanes to defend - and heaps of sun. That covers about 90% of the levels.
I've only got it on the iPhone - so I can't play unlimited. I'm not sure how it would go.
It still has a couple of weaknesses - 2 onions will deal with any walking zombie + pole vaulters. It wont stop:
* vehicles -- use a row of spikes
* gargantuar -- cob cannons, etc.
* Miner Zombies -- These are a pain.
* pogo zombies -- I haven't got a great strategy for them.. - cob cannons, cat-tails, etc. (Or just put a pea-shooter (maybe the reverse one) to deal with these and the miners.
* Flying zombies - the blower plant or the cat-tails. The risk is that it can fall behind your onions - and then eat through all of your sunflowers.
Basically - it works awesome for almost every level.. But probably not for unlimited.
